Electrical connector



Nov. 2, 1965 v E. A. ERIKSSON ELECTRICAL CONNECTOR 3 Sheets-Sheet 1Filed Sept. 24, 1962 INVENTOR.

fies 5 7/4, fem 550M BY P055275 C025 flrroewe/ Nov. 2, 1965 E. A.ERIKSSON ELECTRICAL CONNECTOR 3 Sheets-Sheet 2 Filed Sept. 24, 1962INVENTOR.

EBA 5 7,4 Ez/zsso/v Hrrozws/ H'IHP" I /////l mild Nov. 2, 1965 E. A.ERIKSSON ELECTRICAL CONNECTOR Fiied Sept. 24, 1962 3 Sheets-Sheet SINVENTOR. fax/57x4 521K550 I I I In P w n? i BY Ease/er 5, C025flrrozA/EY United States Patent 3,215,972 ELECTRICAL CONNECTOR Ernst A.Eriksson, 41 Preston Road, Lexington, Mass. Filed Sept. 24, 1962, Ser.No. 225,677 Claims. (Cl. 339-72) This application is acontinuation-in-part of my copending application Serial No. 29,929,filed May 18, 1960, now Patent No. 3,056,941.

This invention relates to electrical connectors and more particularly toconnectors for incorporation in lamps, plugs, fuses and the like,intended for use in internally threaded sockets.

The present invention, like that of the aforementioned application, isconcerned with an electrical connector capable of being introduced intoand withdrawn from a standard threaded electrical socket withoutrotation, while providing secure engagement between the connector andsocket, effectively resisting withdrawal of the connector. The basiccomponents of the connector, whether it comprise a lamp, fuse, plug orother device, are a generally cup-shaped body, a center contact memberand a retaining member for engaging the threaded socket and providing asecond electrical contact. The retaining member is in the form of aspider including a body or base mounted on or within the cup-shapedbody, and two or more radially projecting, thread-engaging, resilientlegs. The legs are deformable to permit insertion of the connector intothe socket and being resilient and biased outwardly, engage the threadsto retain the connector within the socket while permitting the connectorto be withdrawn without rotation.

The present invention has as an object, the provision in an electricalconnector of the type described, a novel and improved retaining elementwhich permits introduction of the connector into a threaded socket withthe application of relatively little force while requiring anappreciably greater, predetermined force to disengage said connectorfrom said socket.

Another object of the invention is to provide in an electricalconnector, a retaining element of the character described requiringrotation of the connector for removal thereof from a socket.

A further object of the invention is to provide an electrical connectorof the type described having a construction characterized by itssimplicity, inexpensiveness and ease of fabrication and assembly,facilitating its manufacture by mass production methods and making itscost competitive with conventional connectors currently employed for thesame purposes.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the product possessing the features,properties and the relation of components which are exemplified in thefollowing detailed disclosure, and the scope of the application of whichwill be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

FIGURE 1 is a perspective view of an electric lamp incorporating, as itsbase, an electrical connector embodying the invention;

FIG. 2 is a partial perspective View, similar to FIG- URE 1,illustrating another embodiment of the connector;

FIG. 3 is a fragmentary sectional view of the lamp of FIGURE 1, thesection being taken substantially in a plane through the center of thelamp;

FIG. 4 is an enlarged sectional view of the connector of FIG. 3 shownengaged in a conventional threaded lamp socket;

FIGS. 5, 6 and 7 are perspective views of different embodiments of acomponent of the connector;

FIGS. 8 and 9 are sectional views similar to FIG. 3 il lustrat-ingdifferent embodiments of the electrical connector;

FIGS. 10 and 11 are sectional views taken along the lines 10-10 and1111, respectively, of FIGS. 8 and 9;

FIG. 12 is a partially exploded and sectioned perspective view of a fuseembodying the electrical connector of the invention;

FIG. 13 is a view similar to FIGS. 5, 6 and 7, illustrating stillanother embodiment of the invention;

FIG. 14 is a partially exploded and sectioned perspective view ofanother embodiment of a lamp base;

FIG. 15 is a view, similar to FIG. 3, showing details of the lamp baseof FIG. 14; and

FIGS. 16 and 17 are sectional views, similar to FIG. 3, illustratingadditional embodiments of a lamp base constructed according to theinvention.

The present invention resides in the design and construction of anelectrical connector in the form of a lamp base, fuse, plug, or thelike, for use in standard threaded electric lamp holders, and dilferingfrom standard threaded connectors, such as lamp bases, in that it isintroduced into and withdrawn from the threaded socket without rotation.The advantages of such an electrical connector, particularly as a lampbase or fuse, have been enumerated in the aforementioned application andinclude safety and convenience both in installation and removal. Theinstant invention teaches the construction of a connector of the typedescribed by which it is possible to predictably control the forcerequired to with-' draw the connector [e.g., a lamp base] from athreaded lamp socket. It is possible to design the connector in such away that the force required to introduce the connector into a socketremains insignificant While the force required for withdrawal may rangefrom an equally insignificant quantity to a force such that withdrawalwithout rotation is a virtual impossibility. In other words, withoutchanging the introductory force required, it is possible to design theconnector so that it must be unscrewed from the socket or so that itbarely remains in the socket and can be withdrawn with little or noeffort.

It has been recognized that, in spite of its numerous and obviousadvantages, the electrical connector of the invention, if it is to findacceptance, must be economically competitive with conventional threadedlamp bases. The structure of the electrical connector is obviously morecomplex than that of standard screw shells making the achievement of theeconomically competitive structure described herein significant initself, since it represents a novel and unobvious structurecharacterized by simplicity, ease of fabrication and assembly, andideally suited to manufactureof inexepnsive materials by mass productionmethods.

Reference is now made to FIGS. 1, 3 and 5 of the drawings wherein thereis illustrated a lamp incorporating the electrical connector of theinvention. The lamp comprises a conventional glass envelope 10 and abase 12 joined to the lamp envelope. Base 12 comprises three components,i.e., a shell 14, a retaining element 16 and a contact 18. The shell isdesigned to fit into the threaded socket while the retaining elementengages the threads to retain the base within the socket and makes oneof the electrical contacts and conatct 18 provides the other electricalconnection for the lamp.

Shell 14 is generally cup shaped, symmetrical about an axis or centerline, is open at one end and includes a peripheral wall 20 flared at theopen end to engage and fit the tapered base portion of lamp envelope 10,and including a generally cylindrical section designed to fit within theminor diameter of a threaded lamp socket; and an end wall designated 22.End wall 22 includes an inwardly projecting tubular support member 24having an axial bore, and is formed with an axial recess 26 in its outersurface communicating with the bore of the support member. Shell 14 isdesigned to be formed of organic plastic materials, such as thephenolics, by conventional molding methods; and peripheral wall 20 andsupport member 24 may taper slightly in thickness from the end walltoward the open end of the shell to facilitate removal from the mold inwhich the shell is formed. Formation of the shell from other moldabledielectric materials such as glass and ceramics in a possibilityalthough shell designs more suited to such materials are shown anddescribed hereinafter. The lamp envelope is secured within the baseshell by a suitable cement or adhesive with the draw-off tube 28, commonto most conventional lamps, extending into the bore of support member24.

Retaining element 16, which performs the functions of retaining the lampin a socket and providing an electrical connection, takes the form of aspider having a base or body 30 and a plurality of legs 32 extendingradially from the body and symmetrically arranged with respect to anaxis through the center line or axis of the lamp base. The retainingelement is shown in FIGURE 1 as having four legs while another andequally preferred form of retaining element shown in FIG. 2, forexample, has only two oppositely extending legs. Body 30, in the formshown in FIGS. 1, 3, 4 and 5, is generally circular, is formed with anaxial hole 34, is engaged around support member 24, and disposed againstthe inner surface of end wall 22. Each of legs 32 includes threesections, these being a first section 36 extending from body 30outwardly and toward the open end of the shell, a second or intermediatesection 38 also extending outwardly and toward the open end of theshell, and a third or end section 40 extending inwardly and away fromend wall 22. The second and third sections of each leg comprise, and arejoined at, a bent portion which engages the threads of the lamp socketmaking an electrical connection and retaining the lamp in the socket.Retaining element 16 is formed of a resilient, conductive material,specifically sheet metal, and is adapted to fabrication by conventionalmetal forming methods with a minimum of operations to be performed.

Shell 14 is provided with a plurality of axial slots 42, one for each oflegs 32, formed in peripheral wall 20 and extending from end wall 22toward the open end of the shell. Each of legs 32 extends from the shellradially through a slot and thence (radially) back into the shell withthe bent portion formed by the second and third sections disposedexterior of the shell. Each of slots 42 has a width approximately equalto the width of a leg 32 and a length sufficient to permit limited axialmovement of the leg engaged therein. In the form shown in FIG. 4, theretaining element is loosely engaged in the shell and is free to movetherein, being retained with the shell by virtue of the engagement oflegs 32 within slots 42. Introduction of the retaining element into theshell is a relatively simple matter since the legs are deformable, andthe movable mounting of the element 16 helps to insure engagement of allof the legs with threads of the socket as the element is free toposition itself. In an alternative embodiment, the retaining element maybe fixedly secured within the shell, e. g., by forcing body 30 towardend wall 22 in surrounding engagement with support member 24. In such anembodiment, the lengths of legs 32 may be varied so that the positionsof the bent portions with respect to the end wall on base 36 of theretaining element correspond to the varying position of portions of athread. In other words, the bent portions of the four legs, insuccession around element 16, are spaced from the base 30 by incrementsof A of the thread pitch. In an embodiment having two legs, one bentportion of one leg would be spaced from the base by an added amountequal to /2 the thread pitch so that both legs engage portions of thesame thread 180 apart.

Introduction of the connector into a standard threaded socket,designated 48 in FIG. 4, requires only the relatively little forceneeded to deform legs 32 inwardly and overcome any friction between thelegs and the threaded socket. However, the force required to withdrawthe connector can be varied from very little, i.e., equal to theintroductory force, to a force which, if applied, would result instructural failure of the lamp assembly, and which necessitates rotationof the connector to achieve its removal from a threaded socket. Ofcourse, the desired force lies between these two extremes and isdetermined by the configuration of the legs, particularly the directionsin which the legs extend into engagement with the socket threads. Thebent portion of each leg at the juncture of second and third sections 38and 40 is shaped to conform to the root and inner face of a socketthread as shown in FIG. 4 and to be tangent to the thread profile at apoint, designated 44, on the inner face of the thread where thecurvature of the thread profile changes from a concave to a convexcurve. This bent portion of each leg may also be provided with aspherical dimple 46, as shown in FIG. 5, to better conform to the threadprofile.

The forces tending to resist withdrawal of the retaining element from asocket are directed through point 44 in a direction normal to the threadprofile at that point. In order for withdrawal to be accomplished, eachleg 32 must be deformed inwardly about the point at the end of firstsection 36 at which the leg joins the body of retaining element 16. Theforce resisting withdrawal and hence, tending to bend or deform the leg,can be resolved into two components, one acting along a line betweenpoint 44 and the end of first section 36; and a second component tendingto deform leg 32 inwardly about the end of first section 36. Themagnitude of this lastmentioned deforming force is, of course, afunction of the angle, designated on, subtended by a line tangent to thethread profile at point 44 and a line from point 44 through a point atthe end of first section 36 where the latter joins base 30 of theretaining element. In order for the connector to be withdrawn, angle orshould be less than since at angles of 90 or greater, there is no forcecomponent tending to bend the leg inwardly, and this component becomesgreater as angle or is decreased, thereby reducing the force requiredfor withdrawal.

The force required for withdrawal is, of course, dependent to a lesserextent on the stiffness and resilience of the material comprising theretaining element and the friction between the legs and the socket.However, these factors are a minor consideration in comparison to angleon in determining the force required for withdrawal. Although each oflegs 32 may be substantially straight, they are illustrated as beingbent in order to accommodate the thread profile and insure engagement ofthe leg only at the inner face of a thread at end section 40 and thebend of said section and intermediate section 38. Any tendency of theleg to bend at the juncture of first and second sections 36 and 38 canbe compensated for by forming the leg of a more rigid material so thatthe precise configuration of the leg remains a minor consideration incomparison to angle a which remains the major factor in determining theforce required for withdrawal; and which in itself, determines the anglebetween the first and second sections of the leg. Angle a can be variedfrom a value of 90 (or greater), at which the resultant force tending tobend the leg is directed along a line through point 44 and the base endof the leg, or outwardly, making withdrawal, without rotation, a virtualimpossibility; to approximately 40 at which the withdrawal force is veryslight and is largely dependent on the resilience of the leg and henceis a function of the force required to overcome the outward spring forceexerted by the leg. A preferred angle a for the legs of a retainingelement having desirable retention characteristics and illustrated inFIG. 4, is approximately 75, and the force required for withdrawal isaffected only slightly by the stiffness of the material comprising theretaining element.

Retaining element 16, as previously noted, functions as one electricalcontact and one of the pigtails or leads, designated 50, of the lamp isjoined to the retaining elernent either at the body or at one of thelegs. In the form shown in FIGS. 3, 4 and 5, this electrical connectionis achieved by lancing a leg, as shown at 52, and inserting lead 50through the lanced portion of the leg and, if desired, the outer end oflead 50 extending through the lanced portion of the leg may be solderedto the outer surface thereof. Another suggested method is soldering,either to the body or to a leg.

The other electrical contact 18 is in the form of a conical springformed of metal ribbon and engaged in recess 26. The other pigtail orlead 54 of the lamp extends through the bore of support member 24 intorecess 26 where the lead is connected, for example, by soldering, tocontact 18. Contact 18, comprising an axially compressible spring,insures good contact with the outer contact, designated 56, of thethreaded lamp socket.

A number of different forms of retaining element 16, designed for usewith shell 14 are conceivable and include an element formed from wire asshown in FIG. 6. The body of the wire retaining element comprises anintermediate section of a length of wire formed into a loop 58 while theend sections 60 of the wire comprise the legs, and are formed inaccordance with the same considerations as apply to legs formed of sheetmetal. Loop 58 is designed to encircle support member 24 while endsections 60 extend into engagement with the threaded socket to make anelectrical contact and retain the connector in the socket.

In alternative embodiments of the connector shown in FIGS. 2, and 8through 11, the retaining element is mounted on the exterior of the endwall of the shell. The shell, in the form shown in FIGS. 2, 8 and 10,and designated 62, is basically the same as shell 14 previouslydescribed, and differs therefrom by the provision on the outside of endwall 64 of a cylindrical support member 66 surrounding recess 68 inwhich a conical contact spring 70 is engaged. The retaining element,designated 72 (shown in FIG. 7) includes a circular body 74 having acenter opening 76 engaged around support member 66 and is secured to endwall 64 by eyelets 78 extending through the end wall. Retaining element72 includes a pair of legs 80, fabricated according to the invenion andextending within and from axial slots 82 formed in the peripheral wall84 of shell 62. One of the leads 86 of the lamp is threaded through oneof eyelets 78 where lead 86 is soldered to make an electrical connectionbetween the lamp and element 72. In order to lessen the cost of theshell by reducing the material, e.g., organic plastic; to facilitateaccess, during assembly, to the interior of the shell; and to providefor ventilation and hence, cooler operation, end wall 64 is formed witha plurality of openings 88.

Another and somewhat similar embodiment of the connector is shown inFIGS. 9 and 11 as comprising a shell 90 having a flared peripheral wall92 for holding the lamp envelope, and an end section 94 which may bedescribed as a relatively thick end wall. End section 94 includes anaxial bore 96 communicating with an axial recess 98 in which contactspring 70 is engaged, and an annular lip 100 on the outer end surface ofsection 94 surrounding recess 98. The ring-like body 74 of a retainingelement 72 is secured in surrounding engagement with lip 100 to endsection 94 by elongated eyelets 78. The legs 80 of the retaining elementextend within and from axial recesses 102 in end section 94. Shell 90 isdesigned to be formed by molding and especially lends itself tofabrication of glass and ceramics as well as organic plastic material.In order to conserve materials, provide for access and promote aircirculation within the connector, end member 94 is formed with a pair ofopenings 104, shaped so that the shell is, in effect, a tube open atboth ends and having a bridge extending from side to side for supportingthe retaining element and contact spring. Electrical connections withthe lamp are made by way of leads extending through one of the eyeletsto retaining element 72 and through bore 96 and recess 98 to contactspring 70.

The electrical connector of the invention is shown in FIG. 12 asembodied in a fuse comprising a generally cup-shaped upper section 106having an end wall 108 and a skirt 110; and a base section 112 includingan end por tion 114 and a support member 116 which, in the assembledposition of the fuse, extends within upper, section 106. The fuse bodyis designed to be formed of glass or organic plastic materials or acombination of both, i.e., upper section 106 of glass and base section112 of organic plastic, by conventional molding methods. End portion 114of base section 112 is provided on its outer end with a recess (notshown) in which is engaged a conical spring contact 118 and supportmember 116 is provided with a central bore 120 communicating with theaforementioned recess and in which is mounted a conducting element 122electrically coupled with spring contact 118. The fuse includes aretaining element 124 shown in detail in FIG. 13 and comprising a base126 having an opening 128 corresponding in size and shape to the crosssection of support member 116 and adapted to be engaged around thesupport member. Retaining element 124 includes a pair of legs 130constructed in accordance with the considerations previously described.The cross-sectional configuration of support member 116, base 126 andopening 128 is approximately rectangular with the ends rounded ratherthan straight lines, corresponding to the generally circularconfiguration of fuses and fuse sockets. The base 126 of retainingelement 124 is engaged in a recess in the upper surface of end portion114. The fuse includes a fusable link 132 connected at one end toconducting element 122 and at its other end to a second conductingelement 134, which extends parallel to the axis of the fuse outside ofsupport member 116 and includes an end section located in contact withbase 126 of retaining element 124. Fusable link 132 and conductingelements 122 and 134 may comprise a single generally U-shaped strip ofmetal with the fusable link suitably formed to provide the requisitecurrent carrying capacity. The inner wall of skirt 110 is shaped toconform to the outer surface of support member 116, so that the skirtretains second conducting element 134 and retaining element 124 in theposition shown by engaging the second conducting element located in arecess in support member 116 between the support member and the skirtand engaging retaining element 124 between end portion 114 and the edgeof the skirt. The skirt is provided with axial recesses 136 in its outersurface for accommodating legs 130 in the manner described heretofore,and upper section 106 and base section 112 are preferably securedtogether in the assembled condition by a suitable adhesive, although aforce fit may prove satisfactory.

The electrical connector of the invention, designed as a lamp base, maycomprise a body or shell formed of two parts rather than a single part.Such a construction shown in FIGS. 14 and 15 is particularly adapted tofabrication from glass as well as organic plastic material or acombination of both materials. This lamp base shell, designated 138,comprises an upper section 140 preferably formed of glass and a basesection 142 which may also be formed of glass or, if desired, anydielectric material including ceramics and organic plastics. The uppersection includes a generally circular wall 144 with an upwardlyextending flared skirt 146 which engages the lamp envelope anddownwardly extending inner and outer cylindrical skirts 148 and 150respectively. Wall 144 is provided with a central opening 152communicatingwith the bore of inner skirt 148 and peripheral openings154 communicating with the annular region between the inner and outerskirts. The outer skirt is provided with a pair of axial slots 156 foraccommodating the legs 158 of a retaining element 160 including a base162 and fabricated as shown in FIG. 5, as previously described.

Base section 142 of shell 138 comprises a base portion including anupper surface formed with a cylindrical support member 166 including abore 168 communicating with a recess 169 in the lower or end surface ofbase portion 164 in which is engaged a conical contact spring 170.

Base portion 164 is also provided with a circular lip 712 which isengaged within outer skirt 150, and base 162 of retaining element 160 isengaged around support member 166 between the latter and circular lip172 with legs 158 extending between the inner and outer skirts andoutwardly through slots 156 in the outer skirt. One of the leads fromthe lamp envelope may be soldered to the base of the retaining elementprior to assembly of the base section of the shell into the uppersection of the shell and the two sections of the shell are thereafterretained together by a suitable cement or adhesive, the epoxy compoundsbeing suggested for this purpose. Similarly, the two sections of thefuses shown in FIG. 12 may be retained together by a cement or adhesiveas well as by friction between the inner surface of skirt 110 and theouter surface of support member 116 and second conducting element 134.

FIGS. 16 and 17 illustrate two-part lamp bases each including acup-shaped shell formed of metal rather than a dielectric and a baseformed of a dielectric such as organic plastics, ceramics, glass or thelike. The lamp base shown in FIG. 16 comprises a cup-shaped shell 174having a peripheral wall with an upper flared section 176 for engagingthe base of the lamp envelope and a lower cylindrical section 178 havingaxial slots 180 for accommodating the legs 182 of a retaining element184. Shell 174 can be formed by conventional metal drawing methods andincludes a generally circular end wall 186 having a central opening 188.The lamp base includes an end section 190 comprising a generallycylindrical support tube 192 extending through opening 188 into shell174 and a circular flange 194 secured to the outer end surface of endwall 186. End section 190 is formed of a dielectric material and thebore of tube 192 is divided by an internal flange 196 into inner andouter sections, the outer section accommodating a contact spring 198.Retaining element 18-4 includes a circular base 200 engaged aroundsupport tube 192 on the inside of shell 174 and both base 200 and flange194 are secured to opposite sides of end wall 186 by rivets or eyelets202, One of the leads or pigtails 204 of the lamp is connected to shell174 in the usual manner by being threaded between flared section 178into the lamp envelope from the shell and soldered to the flared sectionof the shell adjacent its edge. In an alternative embodiment, lead 204may be threaded through one of eyelets 202 and soldered to the outer endof the eyelet. End section 190 mounts the other contact element 198 ofthe lamp base electrically insulating the two electrical contacts fromone another.

The lamp base shown in FIG. 17 is basically the same as that of FIG. 16and dilfers thereform in that shell 206 is formed with recesses 208 inits cylindrical section 210, rather than with slots as previouslydescribed, for accommodating the legs 212 of a retaining element 214.The lamp base of FIG. 17 includes an end section 216 similar to endsection 190 previously described, and differing therefrom by virtue ofthe provision of an annular recess 218 in the upper surface of flange220 surrounding support tube 222 for accommodating the base 224 ofretaining element 214. Base 224 of the retaining element is providedwith a pair of holes and flange 220 is formed with projections 226 whichextend through the openings in the base and through similar openings inend wall 228 of shell 206 and are peened over or otherwise flattened attheir ends, for retaining shell 206, retaining element 214 and endsection 216 together. It is suggested that end section 216 be formed ofa thermosetting organic plastic material which is only partially curedand in a thermoplastic state prior to assembly of the shell and endsection. This condition of the end section permits projections 226 to beflattened by the application of heat, and curing of the end section canbe completed after assembly of the lamp base, and may, in fact, occursimultaneously with the curing of the cement employed to adherethe'shell to the lamp envelope.

The connectors of FIGS. 16 and 17 have been illus-- trated as comprisingseparate shells and retaining elements each formed of sheet metal.However, in a modified embodiment (not shown), the shell and retainingelement may comprise a unitary, integral structure with the end wall ofthe shell acting as the base of the retaining element and the legsthereof formed from portions of the cylindrical section of the shell.

While the connector of the invention is especially designed to beemployed in conventional threaded (Edison base) lamp sockets and fuseholders, the inventive principles on which the design is based areequally applicable to connectors intended for use in other types ofsockets, specifically, sockets provided with an internal ridge orshoulder having an inwardly inclined face similar in profile to theprofile of a lamp socket thread. The basic consideration remains,specifically, the angle designated on, subtended by a line tangent tothe thread face at a point thereon through which the retaining force isdirected and another line extending from this point on the thread facethrough the point at which the leg of the retaining element joins thebody of the retaining element. When this angle at is appreciably lessthan the connector can be withdrawn without rotation, and as the angleapproaches 90, the force required for withdrawal increases so that atangles of approximately 90 or greater, the connector must be unscrewedfrom a threaded socket and withdrawal is otherwise impossible withoutactually breaking the connector or device of which it is a component.The connector is relatively simple and inexpensive in its construction,is easy to assemble, can be introduced into and withdrawn from socketsrapidly and conveniently, and is dependable in its function, effectivelyresisting unintentional dislodgement due, for example, to vibration.

Since certain changes may be made in the above product without departingfrom the scope of the invention herein involved, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. An electrical connector for direct axial insertion into andwithdrawal from an internally threaded socket having a thread formcomposed of two circular segments tangent to each other, said connectorcomprising, in combination:

a body shaped to be introduced axially into said socket;

and

a resilient, electrically conductive retaining member having a base andat least a pair of legs extending freely and without support radiallyfrom points on opposite sides of said base;

said base being mounted on said body with each of said legs extendingfrom one of said points on said base radially beyond the periphery ofsaid base in a direction opposite to the direction of insertion intosaid socket;

each of said legs including a first section having an end shaped topresent a surface for engaging a thread of said socket at a point onthe'inwardly inclined face of said thread at which the profile of saidthread face changes from concave to convex;

each of said legs being pivotable with respect to said base about saidpoint on said base and being so formed that when said connector isengaged within said socket, a predetermined angle subtended by a firstline extending from said point on said thread face radially outward andtangent to said thread face at said point thereon and a second line fromsaid point on said thread face to said point on said base, is less than90, the force required to withdraw said connector being proportional tosaid angle.

2. The electrical connector of claim 1 in which each of said legs is soformed that said predetermined angle ranges from 65 to 80 degrees.

3. The electrical connector of claim 1 in which said first section ofeach of said legs is bent inwardly intermediate said end thereof andsaid base.

4. The electrical connector of claim 1 in which said first section ofeach of said legs is substantially linear so that one component of theforce exerted by said leg in resisting withdrawal is directed throughsaid leg from said end to said point on said base.

5. The electrical connector of claim 1 in which said body is constructedto engage the threads of said socket at the minor diameter thereof andsaid retaining member is mounted on said body for limitedomnidirectional movement with respect to said body sufficiently topermit each of said legs to position themselves in engagement with saidthread.

6. The electrical connector of claim 1 in which said retaining member isformed of a length of wire including end sections comprising said legsand an intermediate section in the form of a loop comprising said base.

7. The electrical connector of claim 1 in which said body is formed ofan electrically conductive material and 10 is shaped to fit within saidsocket in contact with said threads.

8. The electrical connector of claim 1 in which said body includes anaxis substantially coincident with the axis of said socket and thedirection of insertion and withdrawal; a resilient electricallyconductive contact element is provided extending from the end of saidbody at said axis for making an electrical contact, said retainingmember is electrically insulated from said contact element.

9. The electrical connector of claim 8 in which said body iselectrically conductive and said electrical contact is electricallyinsulated from said body.

10. The electrical connector of claim 8 in which said ends of said firstsections of said legs are located at different axial distances from saidbase.

References Cited by the Examiner UNITED STATES PATENTS 897,805 9/08Wegner 339-73 1,317,548 9/19 Casper 33972 1,484,360 2/24 Polzien 339721,510,247 9/24 Smith 339-72 1,551,756 9/25 Laskowski a- 33972 1,628,6365/27 Dominick 33972 1,647,355 11/27 Hendry 339-67 1,700,495 1/29 Hayward33972 1,761,344 6/30 Huber 33972 2,071,769 2/37 Schlicker et a1. 3391992,869,097 1/59 Stuart 33999 X 3,056,941 10/62 Eriksson 339-72 JOSEPH D.SEERS, Primary Examiner.

1. AN ELECTRICAL CONNECTOR FOR DIRECT AXIAL INSERTION INTO ANDWITHDRAWAL FROM AN INTERNALLY THREADED SOCKET HAVING A THREAD FORMCOMPOSED OF TWO CIRCULAR SEGMENTS TANGENT TO EACH OTHER, SAID CONNECTORCOMRPISING, IN COMBINATION: A BODY SHAPED TO BE INTRODUCED AXIALLY INTOSAID SOCKET; AND A RESILIENT, ELECTRICALLY CONDUCTIVE RETAINING MEMBERHAVING A BASE AND AT LEAST A PAIR OF LEGS EXTENDING FREELY AND WITHOUTSUPPORT RADIALLY FROM POINTS ON OPPOSITE SIDES OF SAID BASE; SAID BASEBEING MOUNTED ON AID BODY WITH EACH OF SAID LEGS EXTENDING FROM ONE OFSAID POINTS ON SAID BASE RADIALLY BEYOND THE PERIPHERY OF SAID BADE IN ADIRECTION OPPOSITE TO THE DIRECTION OF INSERTION INTO SAID SOCKET; EACHOF SAID LEGS INCLUDING A FIRST SECTION HAVING AN END SHAPED TO PRESENT ASURFACE FOR ENGAGING A THREAD OF SAID SOCKET AT A POINT ON THE INWARDLYINCLINED FACE OF SAID THREAD AT WHICH THE PROFILE OF SAID THREAD FACECHANGES FROM CONCAVE TO CONVEX; EACH OF SAID LEGS BEING PIVOTABLE WITHRESPECT TO SAID BASE ABOUT SAID POINT ON SAID BASE AND BEING SO FORMEDTHAT WHEN SAID CONNECTOR IS ENGAGED WITHIN SAID SOCKET, A PREDETERMINEDANGLE SUBSTENDED BY A FIRST LINE EXTENDING FROM SAID POINT ON SAIDTHREAD FACE RADIALLY OUTWARD AND TANGENT TO AID THREAD FACE AT SAIDPOINT THEREON AND A SECOND LINE FROM SAID POINT ON SAID THREAD FACE TOSAID POINT ON SAID BASE, IS LESS THAN 90*, THE FORCE REQUIRED TOWITHDRAW SAID CONECTOR BEING PROPORTIONAL TO SAID ANGLE.